The largest freshwater lake in the world by volume is Lake Baikal in Siberia, Russia. It holds approximately 20% of the world's unfrozen surface freshwater and reaches depths of over 1,600 meters (5,200 feet). This ancient lake is renowned for its biodiversity, including the unique Baikal seal and various endemic species. Lake Baikal is a UNESCO World Heritage site and offers significant geological and ecological insights, making it a vital area for scientific research and environmental conservation.